.online-center {
    margin-bottom: 30px;
    height: 550px;
    border: 1px solid silver;
    text-align: center;
}

.online-center div:first-child {
    /*margin: 20px 0;*/
}

/*.online-center div:first-child div{*/
/*    float: left;*/
/*}*/
/*.online-center div:first-child div:last-child{*/
/*    float: left;*/
/*}*/
/*得到英文，并改变颜色*/
.online-center div:first-child div:last-child {
    color: orange;
}

/*让“如果您对我们有什么建议、投诉、需求，可以通过留言告诉我们，我们会在第-时间了解并及时与您联系。”两边清楚浮动*/
.online-center div:nth-child(2) {
    /*clear: both;*/
    color: blue;
}

/*使留言框居中，宽度占比80%*/
.online-center div:last-child {
    width: 50%;
    display: inline-block;
    margin: 30px;
}

.online-center div:last-child:nth-child(odd) {
    text-align: left;
}

.online-center div:last-child div:last-child {
    width: 100%;
    text-align: center;
}

input[type=text] {
    border: 1px dashed gray;
    height: 30px;
    width: 100%;
    background-color: #eeeeee;
}

textarea {
    border: 1px dashed gray;
    height: 100px;
    width: 100%;
    background-color: #eeeeee;
}

input[type=button] {
    cursor: pointer;
    width: 150px;
    line-height: 50px;
    background-color: orange;
    margin: auto;
}